Due to DE 199 06 287 A1 a procedure for controlling a combustion engine became known, which has an exhaust gas treating device arranged in its exhaust zone, that contains a particle filter, which retains particles contained in the exhaust gas. For a proper operation of the particle filter a particle loading status has to be known, which can be determined indirectly by the differential pressure present in the particle filter or by model calculations. The regeneration of the particle filter takes place by burning off the particles stored in the particle filter, which happens in the temperature ranges of e.g. 932° F.-1202° F. It is particularly provided that additional fuel is brought into the exhaust zone of the combustion engine, which reacts exothermically as a combustible with the oxygen in the exhaust zone. The fuel is oxidized for example on the catalytically effective surface of a catalyst. On the one hand this increases the temperature of the catalyst, and on the other hand the temperature of the off-gas stream behind the catalyst, which is then admitted to the following particle filter. The catalyst can also be already contained in the particle filter. The fuel arrives for example by at least one fuel injection in the exhaust zone of the combustion engine.
Due to DE 101 08 720 A1 a procedure and a device for operating a particle filter, that is arranged in the exhaust zone of a combustion engine became known, which are based on at least one operating parameter, which provides the condition of the combustion engine and/or the condition of the particle filter, and moreover stipulates a parameter, which describes the intensity of the particle burn. The parameter is compared to a threshold. In the case of an exceeding of the threshold arrangements for declining are initiated, which aim on the encroachments to reduce the oxygen content in the exhaust gas.
Due to DE 103 33 441 A1 a procedure for operating a particle filter, that is arranged in the exhaust zone of a combustion engine became known, which uses a lambda signal, provided by a lambda sensor, as a dimension of the burning off—speed of the particles during the regeneration of the particle filter. The determined dimension is used to control the particle burning off temperature with the objective of preventing an overheating of the particle filter. A nominal value for the lambda signal or for a change of the lambda signal is given. In case of a noticed deviation between the nominal and the actual value, an intervention takes place for example into the position of the throttle valve, into the charge pressure of an exhaust gas turbocharger or into the determination of a exhaust gas recirculation rate. According to one configuration an actuating element is provided, arranged in the exhaust gas conduit, which brings fuel or another oxidant to the off-gas stream.
The invention is based on a procedure for operating a combustion engine, whose exhaust zone, that contains an exhaust gas treating device, is admitted with a reagent at preset operating statuses of the combustion engine and/or of the exhaust gas treating device, and a device for implementing this procedure, which allows the provision of a sufficient amount of the reagent on the one hand, and prevents the damage of the exhaust gas treating device by an overdose on the other hand.
This task is solved for the given situation by the specified characteristics of the independent claims.